In a famous Aesop fable, a tortoise beats a hare in a foot race by taking it slow and steady. An astonishing new video has now captured a real-life tortoise using the same methodical approach to achieve a far more grisly outcome: straight-up biting off a baby bird’s head and devouring the chick whole.
The nightmarish footage is the “first documented observation of a tortoise deliberately attacking and consuming another animal” and represents “an entirely novel behavioural strategy for any tortoise species,” according to a study published on Monday in Current Biology. The video was shot on July 30, 2020, in the forests of Frégate Island in the Seychelles, by Anna Zora, who serves as the island’s deputy conservation and sustainability manager and is a co-author of the paper.
“Studies of wild animals have not recorded any active predation by any tortoise species,” said Zora and co-author Justin Gerlach, director of biology studies at the University of Cambridge’s Peterhouse College, in the study.
“There are reports of Galapagos giant tortoises squashing birds under their carapace and we have heard of tortoises on Aldabra squashing crabs, but these are anecdotal and although it is implied that the act is deliberate, this is unclear,” the team added. “Our observation is the first documentation of deliberate hunting in any tortoise species.”
In the video, an adult female Seychelles giant tortoise purposefully approaches a lesser noddy tern chick with its mouth open, which is a typical aggressive gesture, according to the study. The chick had fallen from its arboreal nest in the treetops, and was left stranded on a log. Though it backed away to the edge of the log and pecked at the tortoise in self defense, the predator ultimately clamped its jaws down on the bird’s head, delivering a fatal bite.
“The chick, now dead, was dropped and the tortoise had to climb off the log to retrieve it,” Zora and Gerlach said in the study. “Once retrieved, the chick was swallowed whole. From first approach to the death of the chick, the interaction took seven minutes in total; the pursuit along the log to the killing of the chick took 92 seconds.”
Tortoises are found across the world and are almost entirely herbivorous. However, the burgeoning population of Seychelles giant tortoises on Frégate have been observed chowing down on chicks before, though Zora is the first to capture the act on film, suggesting it is not an uncommon strategy in this particular woodland habitat.
Frégate might be home to these unusually bloodthirsty tortoises due to extensive environmental restoration efforts on the island, which have led to a boom in both tortoise and tern populations. When tern chicks fall from their tree nests to the dangerous forest floor, they become sitting ducks for a wide variety of predators, including lizards and crabs, and the island’s tortoises seem to have adopted this easy meal into their own diets.
“At present we do not know how extensive the behavior is on Frégate; future studies will determine whether it develops further or expands more widely in the tortoise population,” Zora and Gerlach concluded. “Even if Frégate’s combination of tree-nesting terns and giant tortoise populations may be exceptional, the present observation considerably expands the known behavioural repertoire of tortoises.”